Quick connect fluid couplings are well known in the art. One form of quick disconnect fluid coupling includes a port defining structure, a fluid line, a seal disposed between the fluid line and the port defining structure, and engaging means capable of engaging the fluid line and holding it from relative movement with respect to the port defining structure, the engaging means being of such a design that the parts can be quickly assembled through a snap fit design. To this end, it is typical to provide an undercut in the port defining structure which can be engaged by the engaging means. Typical examples of such prior art designs are shown in U.S. Pat. Nos. 763,317, 2,441,344, 2,444,888, 3,711,125, and 3,826,523. Each of the prior patents mentioned above has disadvantages which have prevented these designs from gaining wide spread acceptance. Thus, for example, U.S. Pat. No. 763,317 requires a coupling sleeve which is threaded on to the port defining structure, the couplng sleeve capturing the seal between adjacent ends of the coupling sleeve and port defining structure. In addition, the engaging means of this patent is relatively complex and costly. The design shown in U.S. Pat. No. 2,441,344 overcomes many of the disadvantages of the prior design but has its own unique disadvantages. Thus, it is required to assemble a sleeve over an outwardly extending abutment on a fluid line, to then assemble a seal on the fluid line, and to then insert the parts into the port defining structure. The axial force required to be applied when assembling must be applied to the sleeve and it is possible that the sleeve could be unduly radially compressed during the application of axial force, which prevents the sleeve from engaging the undercut on the port defining structure. In addition, because of the dimensions illustrated, the fluid line may flex from side to side with respect to the port defining structure to such an extent that a good seal cannot be maintained. In addition, if the seal and sleeve were to be associated with a dunnage plug, which would be utilized to close the port defining structure prior to the insertion of a fluid line, it would be necessary to completely disassemble the seal and sleeve from the dunnage plug and to then insert them onto a fluid line before the final connection could be made. U.S. Pat. No. 2,444,888 has many of the same disadvantages of the U.S. Pat. No. 763,317 patent and U.S. Pat. Nos. 3,711,125 and 3,826,523 have many of the disadvantages of the U.S. Pat. No. 2,441,344 patent.